In prior art, roughed-out framing systems for wooden buildings are known in which, to facilitate installation, the various parts of the framework are prefabricated prior to being transported to the building site. DE specification 35 12 306 A1 presents a lattice-like frame structure in which the vertical components of each wall frame are joined to a top or bottom stringer via a mortise and tenon joint in which both the horizontal top and bottom stringers and the vertical component are provided with round holes into which separate round tenons are fitted. In joints connecting adjacent wall frames at right angles to each other, mortise and tenon joints are used in the top stringers in which e.g. a central mortise of a rectangular cross-section is made in the top side of the top stringer and the end of the wall component to be joined with it is then fitted into this mortise. The task of joining individual components together can be facilitated by providing them with markings allowing the right components to be joined to each other. This prior-art solution has the drawback of being complex and slow. Drilling small holes for the mortise and tenon joints at exactly the correct positions requires great precision and plenty of time. U.S. Pat. No. 5,170,600 presents a prefabricated housing addition in which dovetail joints are used to connect wall frame components to each other and also to other parts of the wall frame. A drawback with this solution is difficult installation, because adapting the dovetail joint so that it will be set in the correct position at both ends of the component at installation time is very difficult. Moreover, both of the aforementioned solutions are only used for rectangular joints in which the frame components are at right angles to each other.